1. Field of the Invention
This invention relates to an antibacterial, antiplaque oral composition. More particularly, it relates to an oral composition containing a substantially water insoluble salicylanilide antibacterial agent effective to inhibit plaque and more particularly to an oral composition containing a halogenated salicylanilide antibacterial agent wherein the oral composition exhibits a reduced tendency to undergo phase separation and exhibits improved antiplaque efficacy.
2. The Prior Art
Dental plaque is a soft deposit which forms on teeth as opposed to calculus which is a hard calcified deposit on teeth. Unlike calculus, plaque may form on any part of the tooth surface, particularly including at the gingival margin. Besides being unsightly, it is implicated in the occurrence of gingivitis.
Salicylanilide compounds have been identified by the art to be effective antiseptics against microorganisms prevalent in dental plaque. For example U.S. Pat. Nos. 4,287,191, 4,358,443 and 4,939,132 disclose that certain salicylanilide compounds such as 5-acylsalicylanilides, 5-alkyl salicylanilides and 5-alkylsulfonyl salicylanilides are highly effective against bacteria prevalent in plaque, including S. mutans. U.S. Pat. Nos. 5,154,917, 5,145,667, and 4,749,562 disclose that halogenated salicylanilide compounds are effective antiplaque agents.
Accordingly, it is highly desirable to include salicylanilide compounds in oral compositions such as toothpastes, gels and mouthrinses. However the salicylanilide compounds are water insoluble and extremely hydrophobic and are incompatible with most conventional oral compositions which are aqueous based formulations containing anionic surfactants such as sodium lauryl sulfate. It has therefore been observed that when aqueous based oral compositions are prepared using a salicylanilide antibacterial agent such as a 5-acylsalicylanilide, there is a tendency for the oral composition to be unstable and separate into two distinct phases either liquid/solid portions or liquid/liquid portions, rendering the oral composition undesirable for use by consumers. When attempts are made to formulate stable oral care products with the salicylanilide compound using a variety of nonionic surfactants it has been determined that the antibacterial efficacy of the compound is compromised.
There is therefore a need in the art to provide oral compositions containing salicylanilide compounds effective for antiplaque activity wherein phase separation of the dentifrice is substantially avoided without compromise of the efficacy of the compound.